Background:Vascular dementia (VaD) is the second most common type of dementia; it has a significant impact on patients and exerts a great social and economic burden. However, there has been no comprehensive systematic review assessing the efficacy and safety of Buyang Huanwu-Tang (Boyang Hwano-Tang, BHT) for VaD. Therefore, this protocol was developed to conduct a comprehensive systematic review and meta-analysis to evaluate the effectiveness and safety of BHT in the treatment of VaD.Methods:We will perform a comprehensive electronic search including MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Allied and Complementary Medicine Database, Cumulative Index to Nursing and Allied Health Literature, PsycARTICLES, Oriental Medicine Advanced Searching Integrated System, Korean Studies Information Service System, Research Information Service System, Korean Medical Database, KMbase, National Digital Science Library, China National Knowledge Infrastructure, Wanfang database, VIP database, Citation Information by NII, and other sources from their inception to November 25, 2020. This systematic review will include only randomized controlled clinical trials of BHT for VaD. The main outcomes will include the Mini-Mental State Examination, Montreal Cognitive Assessment, and Revised Hasegawa's Dementia Scale. Two researchers will independently conduct study selection, data extraction, and appraise the quality and risk of bias of the included studies. A meta-analysis will be conducted using Review Manager version 5.4. The evidence quality of each outcome will be appraised according to the Grades of Recommendation, Assessment, Development, and Evaluation.Results:This study will provide comprehensive understanding of the efficacy and safety of BHT for the treatment of VaD.Conclusions:The findings of this study will provide reliable evidence for clinical application and further study of BHT for VaD.Ethics and dissemination:Ethical approval is not required because individual patient data will not be included in this study. The study findings will be disseminated through conference presentations.OSF registration DOI:10.17605/OSF.IO/NDYGP